Liquid color concentrate for use in particle articles

ABSTRACT

A liquid color concentration for use in plastic articles comprises a non-orthophthalate plasticizer and at least one of a colorant, a functional additive or a special effect pigment.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/645,275, filed May 10, 2012, the entirety ofwhich is hereby incorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to the use of a liquid colorconcentrate for use in plastic articles to impart a desired visualand/or physical effect, such as a process additive, a UV additive and/orcolor.

BACKGROUND

Plastic has taken the place of other materials in a variety ofindustries. In the packaging industry, plastic has replaced glass tominimize breakage, reduce weight, and reduce energy consumed inmanufacturing and transport. In other industries, plastic has replacedmetal to minimize corrosion, reduce weight, and provide color-in-bulkproducts.

Attracting consumers to purchase individually-sized or family-sizedcontainers includes branding and trade dress. Among the elements ofvaluable trade dress is the color of the plastic article. Moreover, suchcolor may need to co-exist with translucency, transparency, or otherspecial effects for the plastic container.

SUMMARY

According to one aspect of the present disclosure, a liquid colorconcentrate for use in plastic articles is provided. The liquid colorconcentrate comprises a non-orthophthalate plasticizer and at one of acolorant, a functional additive or a special effect pigment.

Another aspect of the present disclosure can include a liquid colorconcentrate for use in coloring plastic articles. The liquid colorconcentrate can comprise an amount of 1,4-bis(2-ethylhexyl)benzenedicarboxylate and at least one of a colorant, a functionaladditive or a special effect pigment.

Another aspect of the present disclosure can include a liquid colorconcentrate for use in coloring a polyester article. The liquid colorconcentrate can comprise an amount of 1,4-bis(2-ethylhexyl)benzenedicarboxylate and at least one of a colorant, a functionaladditive or a special effect pigment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomeapparent to those skilled in the art to which the present disclosurerelates upon reading the following description with reference to theaccompanying drawings, in which:

FIG. 1 is an image showing the chemical structure of polyethyleneterephthalate;

FIG. 2 is an image showing the chemical structure of poly(ethylene2,6-naphthalate); and

FIG. 3 is an image showing the chemical structure of1,4-bis(2-ethylhexyl) benzenedicarobxylate.

DETAILED DESCRIPTION

The present disclosure relates generally to the use of a liquid colorconcentrate for use in plastic articles to impart a desired visualand/or physical effect, such as a process additive, a UV additive and/orcolor. One aspect of the present disclosure includes a liquid colorconcentrate comprising a non-orthophthalate plasticizer and at least oneof a colorant, a functional additive or a special effect pigment.Advantageously, the non-orthophthalate plasticizer of the presentdisclosure is highly compatible with certain polymer resins used to formplastic articles, such as polyester articles (e.g., bottles).Historically, ortho-phthalates have been used as plasticizers forpolyvinyl chloride (PVC)-based products, as well as liquid colorcarriers for PVC and polyethylene terephthalate (PET)-based products.The fact that the liquid color concentrate of the present disclosuredoes not include raw phthalates, which have been associated with humaninfertility (e.g., lowered sperm count) is advantageous for reproductivehealth reasons and, thus, provides the public with a safe alternative toortho-phthalate with certain polymer resins (e.g., PET).

In one aspect of the present disclosure, the liquid color concentrateincludes colorant. The colorant can be any combination of one or moreadditives, pigments, and/or dyes. The choice of colorant is dependentupon the desired color, the machine process, molding temperature, andthe end-use of the plastic article.

The science of color is well known to those skilled in the art. Withoutundue experimentation, one can use color matching techniques to identifya particular location in spherical color space. For example, one skilledin the art can digitally map color space using specific polymer carriersand colorants as raw material ingredients. Alternatively, one can makesmall samples (i.e., plaques) for visual review.

Colorants are commercially available from a number of sources well knownto those skilled in the art. Commercially available pigments are wellknown to those skilled in the art and include organic and inorganiccolorant chemistries. Additionally, commercially available dyes are wellknown to those skilled in the art and include all organic chemistries.Commercial sources for pigments and dyes include multinationalcompanies, such as BASF, Bayer, Color-Chem International, Sun Chemical,and Zhuhai Skyhigh Chemicals.

Table 1 lists eight commercially available pigment colorants in avariety of primary and secondary colors.

TABLE 1 Commercial Pigment Colorants Raw Material Name CI Name FamilyCOLOR FDA* TIOXIDE PIGMENT INORGANIC WHITE Y R-FC6 WHITE WHITE 6 REGAL660R PIGMENT ORGANIC N BLACK BLACK 7 POWDER MPC CHANNEL PIGMENT ORGANICY BLACK BLACK 7 HELIOGEN PIGMENT ORGANIC BLUE Y BLUE K7090 BLUE 15:3HELIOGEN PIGMENT ORGANIC BLUE Y BLUE K6903 BLUE 15:1 34L2000 PIGMENTINORGANIC BLUE Y AZURE BLUE BLUE 28 SICOTAN PIGMENT INORGANIC YELLOW YYELLOW BROWN 24 K 2001 FG SICOTAN PIGMENT INORGANIC YELLOW Y YELLOWYELLOW 53 K 1011 *As published by the commercial producer.

Table 2 shows fourteen commercially available dyes.

TABLE 2 Commercial Dye Colorants Raw Material Name CI Name Family ColorFDA* Lambdaplast Solvent Anthraquinone Blue N Blue NL Blue 59 MacrolexSolvent Anthraquinone Blue N Blue RR Blue 97 Granular Macrolex SolventAnthraquinone Green N Green G Green 28 Granular Macrolex SolventAnthraquinone Green N Green 5B Green 3 Granular Macrolex DispersePolymethine Orange N Orange R Orange 47 Granular Macrolex SolventPerinone Orange N Orange 3G Orange 60 Granular Macrolex Solvent PerinoneRed N Red EG Red 135 Granular Macrolex Solvent Perinone Red N Red E2GRed 179 Granular Thermoplast Solvent Anthraquinone Red N Red 454 Red 195Macrolex Red Disperse Anthraquinone Violet N Violet R Violet 26 GranularMacrolex Red Solvent Anthraquinone Violet N Violet B Violet 13 GranularMacrolex Solvent Anthraquinone Violet N Violet 3R Violet 36 Granular KeyPlast Solvent Pyrazolone Yellow N Yellow 3G Yellow 93 Key Plast SolventQuinophthalone Yellow N Yellow AG Yellow 114 *As published by thecommercial producer.

The colorants can be intended for transparent, translucent, and opaqueplastic articles, as well as all opacities therebetween as required byend-use application and/or customer preference.

Achievement of a color match of a plaque with a desired color, from thecreativity of a designer or a pre-arranged color standard, such asPANTONE color standards from an inventory of commercially availablecolorants, is relatively straightforward for a skilled color matcher,even if a few iterations are required to satisfy the customer.

The concentration of the colorant(s) in the liquid color concentrate issignificant for several reasons, such as the relative cost of thecolorant ingredient(s), the need for colorants to be evenly distributedand dispersed throughout the liquid color concentrate, and that theliquid color concentrate have a stable and pourable viscosity, all forconsistent and precise addition (letdown) of the liquid colorconcentrate with the polymer resin during the formation of pre-formbottles or other polyester articles. Letdown ratios can depend upon theconcentration of colorant(s) and/or additives in the liquid colorconcentrate and whether the final molded product or article is intendedto be opaque, translucent, or transparent.

The concentration of colorant after letdown into the final moldedproduct or article can range from about 0.05 to about 0.2 weightpercent, and preferably from about 0.1 to about 0.5 weight percent.

In another aspect of the present disclosure, the liquid colorconcentrate can be molded with a polymer resin. Suitable polymer resinscan comprise a homopolymer or copolymer containing at least one esterfunctional group in its main chain. For example, a polymer resin cancomprise one or more polyesters. Polyesters can be made in the form of athermoplastic or a thermoset.

Suitable polyesters can have an average molecular weight ranging fromabout 100 to about 65000, and preferably from about 150 to about 8000,and most preferably about 192 (i.e., a PET monomer).

The polymer resin can have a glass transition temperature ranging fromabout −15° C. to about 100° C. and preferably from about 10° C. to about80° C., and most preferably about 76° C. (i.e., the glass transitiontemperature PET).

Non-limiting examples of polyesters can include PET (FIG. 1),glycol-modified polyethylene terephthalate (PETG) poly(ethylene2,6-naphthalate) (PEN) (FIG. 2), polytrimethylene terephthalate,polybutylene terephthalate, polyglycolic acid, polylactic acid,polycaprolactone, polyethylene adipate, and polyhydroxyalkanoate.

In one example of the present disclosure, the liquid color concentratecan be molded with PET.

In another example of the present disclosure, the liquid colorconcentrate can be molded with PETG.

In yet another example of the present disclosure, the liquid colorconcentrate can be molded with PEN.

In another aspect of the present disclosure, the liquid colorconcentrate includes a non-orthophthalate plasticizer that is compatiblewith the polymer resin. The amount of the non-orthophthalate plasticizerpresent in a plastic article can be measured as a percentage of thenon-orthophthalate plasticizer in the finished or final plastic article.The non-orthophthalate plasticizer can include a terephthalate, such asbis(2-ethylhexyl)phthalate or 1,4-bis(2-ethylhexyl) benzenedicarobxylate(referred to as DOTP) (FIG. 3), which is commercially available asEASTMAN 168 (Eastman Chemical Company, Kingsport, Tenn.). In oneexample, about 0.01% to about 10% of the non-orthophthalate plasticizercan be present in a plastic article (e.g., a bottle).

In some instances, a transparent letdown ration (LDR) can be as low as0.01 lbs. per 100 lbs (of polymer resin). Thus, for a transparent LDR of0.01 lbs. per 100 lbs., the corresponding percentage ofnon-orthophthalate plasticizer present in the plastic article or beindicated as “0.01% in finished part.” Similarly, if a molder was to usea liquid color concentrate (but without any pigments, additives, etc.)at a 5% LDR, the amount of the non-orthophthalate plasticizer present inthe plastic article would be indicated as “about 5% in the finishedpart”. In other words, one skilled in the art would understand thefollowing calculation in this instance: 100 lbs. of plastic resin plus 5lbs. of a non-orthophthalate plasticizer would yield a total weight of105 lbs.; therefore, one would understand 0.0476% of thenon-orthophthalate plasticizer in final part.

In another aspect, the liquid color concentrate include about 5% toabout 100% (e.g., about 8% to about 99.9%) of the non-orthophthalateplasticizer depending, for example, on the colorant type and loadingnecessary to achieve a desired technical effect. The amount of thenon-orthophthalate plasticizer present in the liquid color concentratecan be measured as a percentage of other additives and/or liquidspresent in the liquid color concentrate. In one example, a white liquidcolor concentrate can be formulated as follows: about 8% DOTP; about 8%plasticizer (e.g., mineral oil or benzoic acid); about 4% suspensionimprovement additive; about 1% thixotrope; and about 79% TiO₂. Inanother example, a transparent liquid color concentrate can beformulated as follows: about 95% DOTP; about 1% Solvent Blue 97; andabout 4% thixotrope.

In another aspect of the present disclosure, the liquid colorconcentrate can additionally or optionally include at least onefunctional additive to improve processing or performance of one or moreconstituents of the liquid color concentrate. For example, functionaladditives for polyester bottles can include anti-oxidants, anti-stats,acetaldehyde scavengers, blowing agents, biocides, exfoliated nanoclays,thickeners, and the like. Generally, minor amounts of such additivesprovide improvement of performance to the liquid color concentrateduring processing with the other ingredients in the polymer resin or inperformance of the molded article after manufacturing. One skilled inthe art can determine the appropriate concentration of one or moreadditives without undue experimentation.

Frequently, preparation of a colored plastic article (e.g., a polyesterarticle) does not involve merely color, but also special effectfeatures, such as granite, translucent, pearls, metallics, fluorescents,iridescents, marbles, etc.

Plastic articles exposed to natural sunlight are exposed to ultravioletrays that can harm the color of the article. Therefore, it is customary(but not required) to include ultraviolet light stabilizers in theliquid color concentrate. The optional additive can add value to theliquid color concentrate as the ultraviolet stabilizer also helpsprotect the plastic article from adverse effects arising from exposureto ultraviolet rays.

Commercially available stabilizers are well known to those skilled inthe art and can include, for example, thermal stabilizers and Tinuvinbrand stabilizers (BASF, Florham Park, N.J.), such as Tinuvin 234stabilizer.

It will be appreciated that known types of mixing and injection moldingmachinery can be used to make the liquid color concentrate and formplastic articles (e.g., colored polyester articles) in the liquid colorconcentrate. Mixing equipment used to make the liquid color concentratecan include any suitable equipment already used in manufacture of liquidproducts. For example, such equipment can include high speed “Cowles”type dispersers, media mills and three-roll mills. Mixing equipment canoperate at mixing speeds ranging from about 100 rpm to about 10,000 rpm,and preferably from about 500 to about 8000 rpm. Mixing equipment canoperate at temperatures ranging from about 25° C. to about 100° C., andpreferably from about 40° C. to about 80° C.

The following example is for the purpose of illustration only and is notintended to limit the scope of the claims, which are appended hereto.

EXAMPLE

Several DOTP-based color concentrates, with letdown ratios up to 5%,were injection molded with polymers (PET, PEN and PETG) with thefollowing results:

Clarity: when measured by a Datacolor SF650 spectrophotometer intransmission mode, the samples all had excellent clarity with no effectversus the clarity of the base polymer resin without the DOTP-basedcolor concentrate.

Viscosity: the viscosity of the DOTP-based color concentrate was at alevel where it would be stable and have good shelf life. It showed gooddispersion of the pigments and good viscosity for pumping.

Processing: the polymers were injection molded with levels up to, andincluding, 5% DOTP without screw slippage and with no change to thepolymers haze.

The liquid blends were made using a lab Cowles type mixer.

From the above description of the disclosure, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes, and modifications are within the skill of the artand are intended to be covered by the appended claims.

1-21. (canceled)
 22. A method of making a liquid color concentratehaving a stable and pourable viscosity, consisting of: mixing acolorant, a non-orthophthalate plasticizer, and optionally one or morefunctional additives in a mixing mill or a “Cowles” type mixer at aspeed of 100 to 10,000 rpms, wherein the functional additive is selectedfrom the group consisting anti-oxidants, anti-stats, acetaldehydescavengers, blowing agents, thickeners, and ultraviolet stabilizers. 23.The method of claim 22, wherein the non-orthophthalate plasticizerterephthalate.
 24. The method of claim 23, wherein the terephthalate is1,4-bis(2-ethylhexyl) benzenedicarboxylate.
 25. The method of claim 22,wherein the liquid color concentrate includes about 8% to about 99.9% ofnon-orthophthalate plasticizer.
 26. A method of making a colored plasticarticle using a liquid color concentrate, comprising: preparing a liquidcolor concentrate using a process consisting of: mixing a colorant, anon-orthophthalate plasticizer, and optionally one or more functionaladditives in a mixing mill or a “Cowles” type mixer at a speed of 100 to10,000 rpms, wherein the functional additive is selected from the groupconsisting anti-oxidants, anti-stats, acetaldehyde scavengers, blowingagents, thickeners, and ultraviolet stabilizers; and molding the liquidcolor concentrate with a polymer resin to provide a colored plasticarticle.
 27. The method of claim 26, wherein the non-orthophthalateplasticizer is a terephthalate.
 28. The method of claim 27, wherein theterephthalate is 1,4-bis(2-ethylhexyl) benzenedicarboxylate.
 29. Themethod of claim 25, wherein the liquid color concentrate includes about8% to about 99.9% of non-orthophthalate plasticizer.
 30. The method ofclaim 26, wherein the colored plastic article includes about 0.01% toabout 10% of the non-orthopthalate plasticizer.
 31. The method of claim26, wherein the polymer resin is a polyester.
 32. The method of claim31, wherein the polyester is selected from the group consisting ofpolyethylene terephthalate, glycol-modified polyethylene terepthalate,and polyethylene 2,6-naphthalate